Conor McGregor is a professional mixed martial artist from Dublin, Ireland. He currently fights in the lightweight division and is based out of Straight Blast Gym in his hometown. He trains with many notable Irish fighters such as John Michael Sheil, Cathal Pendred, Chris Fields and Aisling Daly. Conor is a Brown Belt in Brazilian Jiu-Jitsu. He also trains in both Dublin and Iceland with fellow UFC fighter and current 170-pound prospect Gunnar "Gunni" Nelson.

He was scheduled to face Jim Alers on the 31st of December at Cage Warriors Fighting Championship 51 in Dublin but Alers had to pull out citing a hand injury. McGregor instead faced Ivan Buchinger for the CWFC 155 pound belt. McGregor gave an extremely dominating performance showing off all facets of his mixed martial arts skills finishing Buchinger by KO at 3.40 of round 1.

McGregor was signed by the UFC and would face fellow featherweight prospect Marcus Brimage on the preliminary card of UFC on FUEL TV 9 in Stockholm, Sweden. McGregor would make an impressive statement with his debut knocking Brimage out in the first round to earn himself Knockout Of The Night honors in his debut. His next test would be against Max Holloway when they squared off at UFC on FOX Sports 1. Even though McGregor tore his ACL during the fight he would go on to win a unanimous decision showing his wrestling skills by taking his opponent down and controlling him with surprising ease.

After a nearly 1 year layoff resulting from the injury, McGregor would face Diego Brandao as the main event of UFC Fight Night 46. He would make it 3 in a row in the UFC by finishing Brandao with strikes in the first round. McGregor faced Dustin Poirier on September 27, 2014, at UFC 178. He won via TKO in the first round. The win also earned McGregor his second Performance of the Night bonus award. McGregor would then face Dennis Siver on January 18, 2015, at UFC Fight Night 59. For the third straight time, he would win by TKO and also earn the Performance of the Night bonus. He was then slated to face Jose Aldo at UFC 189, but Aldo withdrew with rib injuries. 2 weeks before the fight he instead opted to face Chad Mendes for the Interim Championship. He knocked Mendes out in the final seconds of round 2. After the fight, you may note that he was approached by Frankie Edgar, who he most likely would have faced if he hadn't taken his hiatus from MMA from 2016-2018.

Before fighting Mendes at UFC 189, Conor was chosen to coach the European team for The Ultimate Fighter Season 22. His team succeeded in wiping out the American team, and his teammate and prodigy Artem Lobov was scheduled to face Saul Rogers in the TUF 22 finale. Due to visa issues Saul was forced to pull out and was replaced by Ryan Hall, who won the fight by UD, much to McGregor's dismay.

McGregor faced UFC featherweight champion, Jose Aldo at UFC 194. He beat him by KO in the first round to earn the Undisputed UFC Featherweight belt. He then faced UFC Lightweight Champ Eddie Alverez for the LW belt, which he promptly claimed by KOing Alverez in the second round, becoming the first UFC fighter to hold belts in two divisions simultaneously. He was stripped of the lightweight belt during UFC 223 and replaced by Khabib Nurmagomedov as LW champion after he won a UD vs Al Iaquinta.

McGregor fought UFC lightweight champion Khabib Nurmagomedov at UFC 229 on October 6th, 2018. Nurmagomedov bested McGregor in the fourth round, submitting him with a neck crank to retain his title. After the fight an altercation occurred in which McGregor was hit in the back of the head by an associate of Nurmagomedov. The highly anticipated fight at the T-Mobile Arena in Las Vegas lived up to financial expectations, selling over 2 million pay-per-view buys according to UFC President Dana White.

On 26 March 2019, McGregor announced his retirement on social media. However, Dana White viewed this announcement as a ploy to secure an ownership stake in the company, with White later suggesting his retirement would not last and that he had been in regular contact with the Irishman and stated he would fight again in the future. McGregor had previously tweeted that he wanted a rematch with Khabib Nurmagomedov and that he would see him in the Octagon.